Gaps & Speeds

[YosemiteSam]

Assuming all other factors are the same (same arrow, same shooter, same draw length, same anchor, properly tuned nock position, etc.), would larger gaps = greater speeds when comparing two different bows?

Seems like it would.  But just wondering if I'm missing something.

[McDave]

Let's say one bow has an arrow velocity of 200 fps and a 50 yard point on.  With everything the same as you indicated, another bow has an arrow velocity of 175 fps and a 40 yard point on.  Both arrows are initially fired at the same angle, because the arrow points are placed on the bullseyes of the 40 and 50 yard targets respectively, so the arrow points and the respective bullseyes are on one straight line.  The arrows start off on the same trajectory, but the slower arrow immediately begins to drop below the faster arrow.  So up to 40 yards, the faster arrow will have a larger gap than the slower arrow.  After 40 yards, the slower arrow will have a larger gap than the faster arrow.

So how do we get a smaller gap for the faster arrow, and take advantage of its flatter trajectory?  We reduce the point on distance, by somehow raising the nock of the arrows so the nocks are closer to the eye of the shooter, by using a fixed crawl, high anchor, etc.  If all of our targets are between 15 and 40 yards, and we make the point on of both arrows the same at 25 yards, then the gap of the faster arrow will be less than the gap of the slower arrow, since the slower arrow will have to have a higher arc to get to the same point on.

[YosemiteSam]

McDave- That was a very detailed response to just about every possible angle of that question.  Thank you!

[BWallace10327]

So the faster bow/arrow combination has a larger gap, but smaller variances between ranges?  I guess that makes sense, but I'm more of a "sight picture" kind of shooter.  That does make sense however, as I have an easier time shooting various ranges with an arrow going 185fps than one going 160.  Thank you McDave.

[McDave]

What you are saying is correct, Brent.  Assuming you have a 50 yard point on and your arrow velocity is 200 fps, your gap at 25 yards may be about 30”.  Your gaps at 20 yards and 30 yards may be about 28” (of course you have to determine this by testing).  

If you have a 40 yard point on and your arrow speed is 175 fps, your gap at 20 yards may be 24”, and your gaps at 15 yards and 25 yards may be 20”.

While it might be nice to think that your trajectory may be relatively flat between 20-30 yards in the first case, I have found it hard to hold consistently at 28-30” below the target.  I make more errors from trying to guess what 28-30” might be under varying circumstances of terrain and lighting than I gain from the 2” rise and fall of the arrow.  I guess that's why Jimmy Blackmon made his video about the fixed crawl; evidently he must have the same problem.  With a fixed crawl, if you can aim at the spot you want to hit and know that you won't be more than 2” off due to range estimation errors, that's a pretty good deal.

It also is a key to understanding why instinctive shooters like Rick Welch can be so accurate.  If their targets are normally between 20-30 yards, and they have an uncanny ability to hold their bows 28-30” below the target without measuring the gap, they can be pretty well assured of hitting within 2-3” of the spot.

My 'imaginary' secondary point of aim with a broadhead arrow is the same from 30 yards to 42 yards with arrows about 10 grains per pound, behind the leg and just below the chest.  How can that be? Visually the deer is smaller as it get further away. We can see a lot more of the arrow than just the point. The latitude, longitude, and the size ratios are all right there for the brain to work with.  That 'imaginary' secondary aiming point will get automatic on those under 30 yard shot very quickly, even though that is where the most change will happen in typical hunting ranges.  Every hunting shot will have variations, the secondary or gap will get you in the ball park, but don't short change your intuition with over thinking arrow speeds and flight patterns. At hunting yardages those changes may not be as much as you may think.  When I had bows with sights, it was easier to gauge variances in loft and wind drift, it was never as much as I would first guess.  The big variable was always me.

[Cyclic-Rivers]

All that stuff is over my head, I was lost after one sentence. I like to point and shoot. I know I'm no help, but this is supposed to be simple and I do my part to keep it that way.
I don't know efoc, trajectory,a arrow speed, heck I usually can't even remember arrow or point weight.

The problem with 'just point and shoot' you are not giving the deer 20 yards and under much of chance to sneak away.  You should be counting serving wraps, running the trigonometry equations on your pocket calculator, digging the allen wrench out of your pocket to adjust the tiller on your ILF, don't forget to dig out that puff bottle to check the wind, just in case you need to adjust for the deer scenting and don't forget to aim well below the deer, because by now it should be well stooped and ready to bust.   I remember a good laugh we had when told a story about one of the guys trying to shoot the big 8 pointer.  he read articles by this target shooter that hunted with target bows, in Bow And Arrow Magazine, Emery somebody.  He paced off distances and marked them with colored ribbons, then gauged his fancy target sight to have a line marked to slide the pin to for the various distances.  The buck came charging in and stopped at the blue ribbon, he moved his pin to the blue line. No wait the buck is now closer to the red ribbon, he looked down and moved it to the red line.  Something spooked the buck, it ran right past his tree stand, then turned around and came back. It stopped half way between his tree and the closest ribbons, the white ribbon. He looked at his bow sight and didn't know what to do.  Then he had a brain storm, "I will wait until it gets to being even with one the white ribbons".  He had it all figured out, he looked and the buck was gone.

[Thumper Dunker]

Originally posted by pavan:
The problem with 'just point and shoot' you are not giving the deer 20 yards and under much of chance to sneak away.  You should be counting serving wraps, running the trigonometry equations on your pocket calculator, digging the allen wrench out of your pocket to adjust the tiller on your ILF, don't forget to dig out that puff bottle to check the wind, just in case you need to adjust for the deer scenting and don't forget to aim well below the deer, because by now it should be well stooped and ready to bust.   I remember a good laugh we had when told a story about one of the guys trying to shoot the big 8 pointer.  he read articles by this target shooter that hunted with target bows, in Bow And Arrow Magazine, Emery somebody.  He paced off distances and marked them with colored ribbons, then gauged his fancy target sight to have a line marked to slide the pin to for the various distances.  The buck came charging in and stopped at the blue ribbon, he moved his pin to the blue line. No wait the buck is now closer to the red ribbon, he looked down and moved it to the red line.  Something spooked the buck, it ran right past his tree stand, then turned around and came back. It stopped half way between his tree and the closest ribbons, the white ribbon. He looked at his bow sight and didn't know what to do.  Then he had a brain storm, "I will wait until it gets to being even with one the white ribbons".  He had it all figured out, he looked and the buck was gone.

Yup.